You can use the URL of the notes: //, which will work for users with the latest versions of the Notes client. You can use this URL format to start the database (or open a known document in the database), whose file path is known. Unfortunately, for creating an email document in the user's current mailbox, the NSF path will be different for each user. But there is a method that you can use if you have a Notes server in your environment. You can link the link on your page to a static Notes database, in which the "OnDatabaseOpen" event handler is configured to find the path to the user's mailbox, and then redirect the user there. These are a few steps - not as simple as mailto: URL - but if you are desperate, it can be made to work.